The invention relates to an upholstery support for a seat or a seating bench, especially for use in a vehicle.
An upholstery support such as this is known, for example, from DE 195 41 999-A1 (B64D11/06). The latter describes an upholstery support designed as a seat component, one which is in the form of a shell and may consist of plastic or sheet metal. The upholstery support described in this reference is preferably a component of an aircraft passenger seat. It may be inferred from this reference that an especially light construction may be obtained with the configuration described.
Another structure for a light-weight seat has been described in a lecture, xe2x80x9cModern fiber materials and plastics on the vehicle seatxe2x80x9d (Kmitta, Haus der Technik, Vehicle Seat Symposium of Sep. 27/28 1994, Event Number 30-735-56-4). FIG. 15 illustrates a so-called hybrid back rest in which use is made of a metal structural component absorbing stress and torque, a component joined to a real rigidifying high-resistance foam. With respect to its construction the metal structure shown there is comparable to that of a lightweight seat as described on page 52 of Autozeitung [Automotive Journal] October 1997. The seat frame shown there is of more or less conventional design, and, in order to reduce weight, is made of a light metal, preferably diecast magnesium.
U.S. Pat. No. 5,100,204 and U.S. Pat. No. 4,568,124 disclose upholstery supports which are in tubular form for achievement of lightweight construction. U.S. Pat. No. 4,568,124 discloses use of the relatively unstable construction in order to obtain specific pneumatic shock absorption properties. U.S. Pat. No. 5,100,204 describes mounting of external reinforcing elements on the upholstery support in order to stabilize it.
DE-9012858.3-U1 shows an upholstery support of single-layer design onto which is molded a pouch into which an absorbing element, preferably of high-resistance foam, may be inserted to form a support for the lumbar vertebrae.
The object of the invention is development of additional means of weight reduction for upholstery supports of seats or seating benches.
This object is attained with an upholstery support if characterized by the features described in claim 1. The dependent claims relate to especially expedient developments of the invention.
It is claimed for the invention that the upholstery support is of sandwich design, in which a shell mold receiving large-area padding on one side and a rear-wall element on the other enclose a molded foam element between them. This molded foam element is preferably in the form of high-resistance foam with a so-called volume weight of 10 to 30 grams per liter. The high-resistance foam element may be designed either as an insert which is introduced between the shell mold and the rear-wall element or is injected into the cavity formed by the shell mold and the rear-wall element.
The fact that entirely conventional forming technology may be employed to produce the shell mold and the rear wall element made of light sheet metal plates, for example, is a particular advantage of the upholstery support claimed for the invention. Similarly, a suitably shaped high-resistance foam block may be conventionally manufactured and then either introduced between the sheet metal elements as a separate component or cemented to at least one of the sheet metal elements. Joining of the sheet metal elements may be effected, for example, by adhesion and/or riveting and/or welding and/or folding.
In a preferred development of the invention the shell mold, for example, is partly perforated, especially in the area of a cavity receiving the element introduced. As a result of this perforation, additional weight reduction is achieved, and also the moisture resulting from passenger perspiration can escape into the high-resistance foam block element. An air conditioning function may thus also be assigned to the upholstery support claimed for the invention.
The sandwich structure here proposed results in extremely high strength along with very low structural weight, especially for the reason that the upholstery support as a whole, that is, optionally with the exception of the marginal areas, may be designed to have very thick walls. Particular emphasis is to be placed on the fact that the space requirement for resilient foam for upholstering may be reduced by preshaping the shell mold. Hence the structural volume may be put to a distinctly different use than in the case of conventional seat structures. Application of the upholstery support claimed for the invention results in a distinctly higher proportion of structural volume for the upholstery support and a correspondingly substantially lower proportion for the resilient foam upholstery without the need for sacrificing comfort.
Of particular importance for manufacture and installation of the upholstery supports claimed for the invention are high-resistance foam parts which are designed as aggregate vehicles. For example, foam may be simultaneously injected in advance into support elements for flexible foam upholstery, headrest guides, or supports for automatic seat belt winders, and optionally metal stiffening elements. Thus, an aggregate support prepared in this manner may be positioned, completely preassembled, between the shell mold and rear wall element to produce another subassembly. The flexible foam upholstery may then be fastened to suitably prepared mountings by simple clamps or conventional bracing. Fastening of the flexible foam upholstery by means of cementing is also conceivable.
The preferred application for the upholstery supports claimed for the invention are back rests for the back seat benches of motor vehicles. Of heightened importance in this context is the fact that, for example, cargo carried behind the back rest comes up against an upholstery support in the event of sudden vehicle deceleration. One the one hand this support is relatively rigid toward these stresses, and on the other may be incorporated into the structure of the vehicle so as to absorb energy in the case of use of injected-foam link pins. Consequently, no structural changes in or additions to the body of a vehicle need be made to reduce peak loads caused by collisions on impact with loose articles carried in a vehicle. Hence what results in the aggregate is an upholstery support of high rigidity and simultaneously of great ductility. The overall structure of the support alone thus has a high energy absorption potential.